General review about the Fitbit Sense

[SunsetRunner]

I like Fitbit. But after using a Sense for about 8 months, I come to the conclusion that, with all its bells and whistles, Sense was a bite more than Fitbit could chew. And that's a pity, because it's affecting the brand's prestige, in my opinion.

The only feature I find GOOD since the beginning is the new ECG graphs, totally approved by my cardiologist, besides FDA and other countries Health Authorities. But not its Afib auto-detection, though. It works poorly.

SpO2 seems ok and useful, in line with clinical measurements I did.

Steps seem also ok, but who wouldn't expect that after years of experience?

GPS: just bearly enough. But I rather use my phone's GPS, which is clearly more accurate. The question is: could we expect more of a GPS in a smartwach with so many features?

As for the rest?

Heart rate (HR): useful when you learn how to use it and its pitfalls. As with several other features, it's a pity the manual and help pages don't warn you enough about what can often go wrong.

The same with HR dependent features, like Calories and Active Zone Minutes. I find them useful to compare different days, but quite rough, mostly in absolute values. We must learn first what can affect their values.

Resting Heart Rate seems good enough, though. It requires no hand movements, which are the weakest point of HR readings.

Floors: still a disaster. Useless.

As for the other features, I really don't know whether I can trust them or not. So, I just look at them, try the EDA just for curiosity, but don't take them seriously. Why would I?

So, Fitbit: please continue trying to improve Sense's software (many of us are not willing to buy a new expensive Fitbit every year) and be more careful on next devices. Maybe including less but more reliable and accurate features?

(cont.)

BATTERY. In spite of complaints from several users, I think it is still one of Sense's strongest points. Actually, it was one of the main reasons why I chose to buy a Sense, 8 months ago, and on this feature I have not regretted so far. For me, each battery charge lasts from 1 to 3 days, depending on the kind of use and the features I have switched on. GPS, e.g., uses a lot of battery. Not using GPS nor ECG, I easily get 3 days until I reach 25% of total battery charge. Not bad at all, comparing to other competing brands.

[clk1986]

There are other features as well that you left out, yet they may not apply to your use case.

NFC payments.

Google Assistant control.

Voice Call.

Message notifications w/Speech-to-text reply.

Sleep logging.

Weather app.

Relax app.

I'll say, my only real comparison would be Versa Lite vs Sense, and not a Versa2 or Iconic.  But 9 months in, I'm still enjoying my Sense, while the Versa lite (a $100 placeholder until the Sense came out) just felt lacking right out of the gate, and that's coming straight from a Charge HR.

That said, it's a bit spendy.  I'd say $199 (which it has been on sale for a few times recently) would be a great price for people on the fence and $230 should be MSRP. I think mine was $250-$260 from Costco in Nov 2020, that was with $50 or $60 discount. That was my Christmas gift to myself, so I don't feel bad about it and it's been great. Good insights and features, imo. Has made my life run a bit smoother, because I can leave my phone around the house and still receive and reply various messages easily.

EDA is interesting.  It does show HRV.  But as far as what it means for the rest of the session, I have no clue. 

[Jules565]

Fitbit sense the worst piece of crap I have ever spent my money on. Constantly doesn’t Sync, needs to be restarted , weather app never work , find my phone works some times not others ,  just a complete waste of money ,should have bought an Apple Watch for the extra money . So tired of resetting every second morning to sync 

Other things that don’t work , the scan where you put your palm over the screen , Gimmick that never works , there are just too many things about this piece of rubbish that don’t work , buy the cheapest Fitbit possible 

Also the message notifications don’t work and the watch no longer vibrates when my iPhone rings , too many things wrong with this and I don’t have the time to correct them , it’s should just work , mine is going in the rubbish tomorrow 

Moderator edit: merged reply

[clk1986]

Are you using an Android Device or Apple? 

Your issues could be device related, but more than likely it might be an issue with your phones hardware or settings.  I've found the experience to be much better once I upgraded my phone from an Android 8.0 device to Android 10.0 (which got upgraded to 11.0). 

Since Google acquired FB, I'd expect it to work better on Android (though it was already primarily geared toward Android) and I would expect some issues with Apple compatibility.  So if you have an Apple phone, I'd generally recommend using Apple Watch.  It just seems like it would smoother experience. 

[SunsetRunner]

Thanks for your replies, you all.

@clk1986, you are right about most of the other Sense features I left out - I just don't use most of them. But use some. Here goes my experience with some of them:

NOTIFICATIONS from phone messages (SMS, Whatsapp, Messenger, Email, Gmail): since I learned how to configure both Fitbit app and Sense, which took an hour or two, they have always worked fine, no problems at all. I never used speech or phone call features, nor music, because I feel I just don't need them and they would just add to Sense's workload and reduce the duration of each battery charge life.

UPDATE: Sometimes notifications start failing to reach Sense, but when that happens, a restart of Sense and, sometimes, the Fitbit app or even the phone have been enough to put them back on track.

UPDATE 2: Sometimes what I described above is not enough. If Sense is bluetooth paired with the phone, I have to unpair it, sync again and so on. I admit I do it in a somewhat chaotic way, by trial and error until it begins working again. There must be a right order to do these steps just once and... voilà! And sure they are described somewhere in Fitbit Help pages and/or in this Community forum. I've seen them, just don't remember where. But it must be not difficult to find it, if you want.

SLEEP LOGGING: I used it every night in the beginning, then changed to use it only once every 2 or 3 nights, or when I want to log a particular night. Apparently, it works just good enough, but:

1) The beginning and ending times are often not accurate. In some sleeping logs that show I was sleeping at a certain time, I know I was awake then.

2) As I don't have any other way to compare the reliability of these logs and adding to all the other Sense glitches, I don't take the details of these logs very seriously. But I find that, in general, the sleep quality number associated to each sleep log matches how well I slept, by feeling it in the morning. But... I didn't need to buy a US$360 Sense to know that (yes, Sense cost me 330 euros in Europe).

The reason why I bought Sense was because I have a heart condition and I really needed some device to have some control on my heart behaviour on my everyday life, 24/7, including (and that was most important) ECG. Sense has been doing a reasonable job for me on this perspective and as a regular watch as well, and I've been better with it than without it, that's the point. But the Heart Rate inaccuracies have already failed me badly a few times, though.

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@SunsetRunner, I agree with you.

My phone also gives me much more accurate and reliable values concerning GPS and distances. Even steps, which is hard for me to understand.

As my heart rate is now very important to me, I have already ordered a Polar H10 chest strap. Not taking chances anymore, Sense has already let me down a few times on that. I'm waiting for H10 to arrive.

Thanks for your feedback. Always helpful.

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@Jules565, I totally understand your frustration. Sense is not exactly a cheap device. Most of us certainly expected something more reliable, more useful and with not as many glitches/bugs as many users report, like yourself. I think I was one of the lucky ones, in spite of everything. The best I can do is suggest Customer Support, using chat. It was very helpful to me last year (with a Versa 2) but we need to have time, take several deep breaths along the process and have a lot of patience, besides it helps a lot reporting everything with every detail possible, even photos, if they can be helpful.

You mention iPhone. I've seen quite a lot of complaints from other users with iPhone as well. I use an android phone, I can't help you there.

But I also read in other forums (not Fitbit) a few quite bad complaints about Apple smartwatches. But I don't remember any useful details. Having said that, I agree with @clk1986 when he says "if you have an Apple phone, I'd generally recommend using Apple Watch".

Competition is fierce on this kind of do-it-all smartwatches, that's for sure.

[Jdsenter]

Going from an Ionic to Sense, my use case might be different, from an exercise Watch, it works most of the times. I really like the Fitbit labs apps, but they are not compatible with Sense, even the Arc clock face. Really the exercise app lost shortcut features, and do to a single button, things that were done on the Ionic, take twice as long on the Sense. Never really used music control (built in music and music apps on phone) but it was handy when I did. GPS seems the same as well as heart rate, sleeping is where the Sense shines. I have learned so much, maybe that is mostly due to premium which lets users see their data better and more detailed. But overall it is a modest upgrade from the Ionic. 

[SunsetRunner]

Thanks, @Jdsenter .

I've worked more than 20 years with electronic instruments taking measurements in the soil and underground, not the human body. It's different, but many aspects are the same. Besides, I'm familiar with the basic concepts of scientific research. My point now is this:

Usually, it is worse to rely on bad readings from a bad instrument than have no instrument at all.

The big question marks on some (many?) of Sense's readings is:

How reliable are they?

How much can we trust them?

For me, the trust comes only when I, or someone I can trust, can confirm them by comparing with the results from a different independent instrument or means.

I've seen on this Community forum (or was it Youtube?) one good analysis of Sense heart rate, comparing it with several other instruments in different situations and showing very clear graphs about it. But it was (or linked) from a user, not from Fitbit. And nothing about all the other parameters provided by Sense.

After all the bugs and glitches I've seen reported in this forum, some of them I experienced myself, and given the quite poor technical feedback from Fitbit, I am not inclined to waste my time analysing and taking conclusions (right or wrong?) based only on Sense's results (sleep, HRV, etc.) when I just have the option to trust them or not, with no way to confirm whether they are right or wrong. For me, that's the point where I am now. Except for the ECG app, which was well studied and approved by some of the best Health Authorities in the world, which we know don't play around with these things. And the results I show regularly to my cardiologist confirm it.

I understand that Fitbit's hands may be tied for commercial reasons. Their competitors are probably reading everything in this Communty forum. But, in the end, we customers must be happy with Fitbit products. And Sense is not a US$100 watch.

[clk1986]

Good point about premium.  Sense comes with 6 months of premium, or at least it did. I didn't use my premium until about 2 months in and it did unlock quite a bit of stuff, mainly in the sleep tracking.  I was supposed to get another free month from doing the Fitbit Sleep Study, which ended earlier this week after 2 weeks of surveys, but not seeing it. So I guess we'll see how nerf'd the Sense becomes at that point.

One thing that I've noticed but didn't expect, is I've been able to pinpoint with the Sense is when I'm getting sick or having an immune response.  My resting HR will be elevated and my HR during sleep will  be above baseline.  My Skin temp will also be much higher.  This happened when I got sick out of the blue and also for both of my Covid shots.  Pretty interesting data. HR and resting HR was elevated for almost a week for each Moderna shot, whereas it went back to normal within 2 days after a bout with some bug.

[SunsetRunner]

Thanks, @clk1986 . That is very useful and reassuring info.

[SunsetRunner]

@SunsetRunner 

This is a good discussion. 

Yes, I agree that the source reading need to be reliable first since all, if not most of the metrics are driven by HR data. Still have some doubts on the Sense's HR readings albeit starting to gain trust ever since comparing the HR readings from my armband HR monitor. During exercise, HR was only +/- 2 to 3 BPM. In my opinion, fairly decent to be used for daily exercise. Others might disagree, in my usage as a recreational runner, it starting to be good enough. 

SPO2 readings daily also are within 1-2% compared to my pulse oximeter. Decent enough for my purposes, a general idea of oxygen saturation, not for medical use. HRV readings taken with my armband monitor using EliteHRV app has been within 5-15 milliseconds. Good enough? Maybe....

Bottom line is, the source readings need to be accurate. One would argue, the Sense is not a medical device, and so it is. Is it good enough for the users? That depends on the individual user and the purpose of interpreting the readings. 

One thing that's still holding me back from jumping ship...the grass is not always greener on the other side. 

If you visit forums of other wearable, they also have their own issues. Guess you can't have your cake and eat it too...LOL. 

Fortunately, haven't experienced hardware issues on the Sense (cracked screen, falling screen, rubber gasket starting to fall apart, ill-fitting wrist bands, etc.). The only hardware issue experienced was the slow charging of the Sense and was remedied by a new charge cable. No issues charging since. 

Still no compelling reason for me to get another wearable....for now (but i am looking at the first opportunity though). 

[Jdsenter]

As far as hardware issues, my Ionic got a chip in the screen, washed my hands, soap got into the display, the screen went black... Got a new screen, removed the old, dried out the Ionic, gave it a good isopropyl vaper bath, waited over a month (this is when I got the Sense), once I was convinced it was dry, used some silicone adhesive and put the new screen on... Now I use the Ionic while the Sense is charging. The sensors are similar enough, give me similar results, also use the heart rate sensors on my Treadmill and Elliptical also give similar results. But none are professional medical devices. Only used Fitbit device since 2017, so can't report on competitive devices, but these are good enough for users, but not medical devices. If I want to know my spo2 or temperature I used medical grade devices, but for good enough the Fitbit works. The Sleep information on the Ionic was limited, but the Sense with premium opened the doors on the information gathered. Very helpful. 

Great Topic, thanks.

[SunsetRunner]

Thanks, @SunsetRunner .

I agree, we can help each others a lot by discussing here these kind of details. The fact is that I like my Sense as well, as a smartwatch it serves well enough my needs, it looks good and I also don't intend to replace it soon.

Just one point. As far as I know, Sense provides SpO2 readings taken only while we sleep.These values can be similar to day time values for healthy people. But people with breathing disorders during sleep, like deep snoring or sleep apnea, may have lower SpO2 values when sleeping and not knowing it. If I'm not wrong, that's what Sense's SpO2 values are useful for, to detect those kind of breathing sleep disorders. If these values are similar to the day time values, taken with a regular pulse oximeter for instance (usually 95%-97% most of the time), than great! But if the sleep values go lower, mainly if they approach 90%, than you should tell that to your doctor on your next appointment, as it can be harmful on the long term. If SpO2 goes below 90%, than you should not delay your visit to the doctor. Sense's Help pages on SpO2 explain something about that.

[Jdsenter]

As far as SpO2/Temperature, I have a medical device that with a thumb reader that if used all night can print out a result, I have not tried during sleep, but maybe sometime I will try it and see if Sense is close to it's results. With the data collected and that I now have access to (because of premium), I will see if I can make trends like sickness or vaccine results.

[SunsetRunner]

Thanks @Jdsenter .

[clk1986]

Would be interesting to see the results.  Just make sure you put it on the same arm for consistent results.

I say this because I notice significant peaks and valleys in my skin temp and my best guess is that it's from me sleeping weird and my arm losing circulation--Because I wake up often with sleeping limbs.

Pre-Sense, I actually woke up one night sweating, nausea, stomachs pain and both arms were completely numb.  I was convinced I was having a heart attack.  Nope, turns out I ate too much Tapatio Hot Sauce with my chips at dinner and didn't finish it off with any type of milk and it was just a coincidence that both my arms fell asleep. 15 minutes to the porcelain gods cured me. XD 

Have a good day.

[SunsetRunner]

Following your last posts, @Jdsenter  and @clk1986 :

TEMPERATURE. The sleeping skin values I get with Sense during the night are usually within +/- 0.5 degree, which don't bother me. But once and a awhile I have 2 degrees below average. I find it a bit too much and found no obvious reason for that. I just wondered if I slept most of that night with that arm outside the blanket. Or maybe your numb arm explanation applies here. Anyway, as the following night the temperature goes back to the usual few decimals from the average, I just forget it. Anyway, I never looked for an explanation on the Help pages, never bothered much with Sense's temperature. I also prefer to use a medical grade thermometer when I feel I can be feverish.

Maybe this temperature is more useful to women, due to their ovulation cycle.

I don't know much about HRV (heart rate variability), but here is a great post about it.

Also remind that HRV and other parameters are taken by Sense during our sleep and some or all of these values can be different from those taken while we are awake.

Apparently, Fitbit doesn't provide much information about how we should interpret these values, which are more related to health than to the smartwatch. We have to search and learn elsewhere for details.

But based on Fitbit Help pages, for HRV the key point seems to be that each person has its own base level and while HRV values are near that base level, or within his/her personal range, everything is OK. It seems a bit simplistic to me and Fitbit just playing on the safe side, but better than nothing, anyway.

On the thread of the link above, most users report HRV values on the 20's range, which are about the same I get. What we find searching the net on sites that can be trusted, usually the value of 50 or more is mentioned as reference for healthy young people. I wonder whether the difference (50 to 20) is not just a normal one between day time and sleeping time values. Or is it another Sense bug? I really don't know and haven't found yet any explanation for that.

[SunsetRunner]

Thought I'd show an example of a momentary spike in HR reading for the Sense in the beginning of the exercise/run. Watch is worn 2 finger widths from the wrist bone. The rest of the run appears HR to be somewhat stable. 

 

[SunsetRunner]

For comparison, here is the HR reading from my arm band HR monitor during the same exercise. No spikes on HR from the armband. 

Now, is the Sense or armband accurate? Chart only shows the spike on the Sense during the beginning of the exercise. For me, as a recreational runner, Sense is "good enough" for my purposes, at the moment.

 

[SunsetRunner]

@SunsetRunner , I vote for the armband.

Now I show you four Sense HR records of slow walks by a guy having heart issues, so he has to take it slowly.

Apart from the absolute HR values, completely different from yours, the spikes at the beginning are there too on the first two records. It doesn't happen always and fortunately these are easy to identify and isolate from the rest of the record. Taking this into account, it's good enough for me.

But sometimes there are more tricky HR spikes, even plateaus, whose identification is better to be done during the walk, otherwise it may leave me with doubts. The other two images show what I think are artificial artifacts too, because I double-checked my HR at the time with fingers and chronometer. See the sharp rises and descents, hard to explain otherwise.

Still without armband or chest strap to compare, though...

 

[SunsetRunner]

Another false HR spike during a quiet walk: